变速运行下抽油机系统力学参数相关性分析

抽油机变速运行技术能降低电机的峰值功率,改善抽油系统的运行状况。目前在国内外各大油田试验推广,以实现抽油系统的节能降载,提高抽油机的系统效率。为了分析在变速运行过程中造成电机峰值功率降低的主要因素,将整个抽油系统划分为3个子节点,通过现场试验的方式,测取各节点的力学参数变化情况,并引入变异系数的概念,用来描述和对比各项数据的离散程度的大小。在进行数据处理时,结合统计学理论,使用SPSS软件对变化的力学参数作相关性分析,结果表明电机功率的变化与转速变化具有强相关性,电机扭矩的变化与电机的惯性扭矩同样具有强相关性,而减速箱扭矩的变化与曲柄惯性扭矩以及游梁惯性扭矩具有极弱相关性,在分析和对比悬点速度曲线时发现悬点的梯形台式平稳运行有助于降低减速箱扭矩的波动。

CORRELATION ANALYSIS ON THE MECHANICAL PARAMETERS OF THE OIL PUMPING SYSTEM UNDER THE VARIABLE-SPEED OPERATING CONDITION

For the oil pumping unit,the variable-speed operating technique can decrease the peak power of the motor and improve the operation condition of the pumping system.At present,this technique is widely tested and generalized in the big fields at home and abroad so as to achieve the goals of the energy saving,load reduction and efficiency rising for the system.In order to find out the dominant factor in the motor's peak power decreasing under the variable-speed operating condition,the whole system was divided into three sections.With the help of the field test,the changes of the mechanical parameters in each section were measured,and at the same time,the concept of the variation coefficient was introduced for the characterization and comparison of the discrete degree of each data.In the process of the data processing,integrated with statistical theory and with the help of SPSS Software,the correlation analyses on the changed mechanical parameters were conducted,the results show that there is the strong correlation between the variations of the motor power and rotate speed,so as to the changes of the motor torque and its inertia torque.On the contrary,the torque variation of the gear box shows extremely weak relativity with the inertia torques of the crank and the walking beam.When comparing the velocity curves of the polished rod,it was found that the smooth trapezium-shape bench operation of the rod can help to decrease the torque fluctuation of the gear box.